As is known in the art, there are a variety of known systems for determining position. For example, Global Positioning Satellite (GPS) systems can identify the coordinates of a person having a GPS device. GPS techniques have also been proposed for determining the position of mobile stations in near real-time. However, such an approach requires specialized hardware components and antennas that add cost, size, weight and extra power consumption to mobile terminals. In addition, GPS devices can disrupt wireless communication, e.g., phone calls from a mobile phone.
Furthermore, since GPS is a satellite-based position determination system, operation depends upon the ‘visibility’ of a sufficient number of satellites with a proper geometry to provide accurate positional information. For example, it is known that satellites distributed evenly along the horizon provide the best geometry for accurate positioning. However, satellites in this position are the most likely to be blocked by trees or buildings. Overhead satellites are most likely to provide the strongest signals, but several closely spaced overhead satellites result in the worst ‘dilution of precision’ in determining position. And since the satellites are constantly in motion, relative to the mobile station and relative to each other, location accuracy varies significantly with time.
It would, therefore, be desirable to provide a system that overcomes the aforesaid and other disadvantages.